using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using UnityEngine;
using System.Runtime.InteropServices;

namespace SmartBowSDK
{
    /// <summary>
    /// Windows连接BluetoothLE
    /// 我的扫描逻辑默认了读写特征都在同一服务下
    /// </summary>
    public class BleWinHelper : MonoBehaviour
    {
        private const string LogTag = "BleWinHelper-Log: ";
        private static void Log(string text)
        {
            Debug.Log(LogTag + text);
        }
        private static void Warn(string text)
        {
            Debug.LogWarning(LogTag + text);
        }
        private static void Error(string text)
        {
            Debug.Log(LogTag + text);
        }

        private string targetDeviceName = "Bbow_20210501";
        private string targetService = "{0000fff0-0000-1000-8000-00805f9b34fb}";
        private string targetCharacteristicsNotify = "{0000fff1-0000-1000-8000-00805f9b34fb}";
        private string targetCharacteristicsWrite = "{0000fff2-0000-1000-8000-00805f9b34fb}";

        private bool isConnectLocking = false;
        private bool isScanningDevices = false;
        private bool isScanningServices = false;
        private bool isScanningCharacteristics = false;
        private bool isSubscribed = false;
        private bool isSubscribing = false;

        private string lastError = null;

        private string selectedDeviceId = null;

        private Dictionary<string, Dictionary<string, string>> deviceList = new Dictionary<string, Dictionary<string, string>>();
        private List<string> serviceList = new List<string>();
        private List<string> characteristicsList = new List<string>();

        private float _connectedTime = 0;
        private float _receiveDataTime = 0;
        private float _heartBeatInterval = 0;

        private Action OnConnected;
        /// <summary>
        /// 主动调用Disconnect()不会触发该委托
        /// </summary>
        private Action OnConnectionFailed;
        private Action<byte[]> OnCharacteristicChanged;

        public static BleWinHelper RegisterTo(GameObject o)
        {
            if (_Instance)
            {
                Error("Register fail, because only one can be registered.");
                return null;
            }
            BleWinHelper comp = o.AddComponent<BleWinHelper>();
            BluetoothWindows.Connect = comp.Connect;
            BluetoothWindows.Disconnect = comp.Disconnect;
            BluetoothWindows.Write = comp.Write;
            comp.OnConnected = () => BluetoothWindows.OnConnected?.Invoke();
            comp.OnConnectionFailed = () => BluetoothWindows.OnConnectionFailed?.Invoke();
            comp.OnCharacteristicChanged = (bytes) => BluetoothWindows.OnCharacteristicChanged?.Invoke(bytes);
            return comp;
        }

        /// <summary>
        /// 设置心跳检测
        /// 1.每次收到的蓝牙数据都视为心跳
        /// 2.帮助触发蓝牙断开监听
        /// </summary>
        /// <param name="interval">心跳检测间隔</param>
        public void SetHeartBeat(float interval)
        {
            _heartBeatInterval = interval;
        }

        private static BleWinHelper _Instance;

        void Awake()
        {
            _Instance = this;
        }

        void OnDestroy()
        {
            if (_Instance == this) _Instance = null;
            BleApi.Quit();
        }

        void Update()
        {
            BleApi.ScanStatus status;
            if (isScanningDevices)
            {
                BleApi.DeviceUpdate res = new BleApi.DeviceUpdate();
                do
                {
                    status = BleApi.PollDevice(ref res, false);
                    if (status == BleApi.ScanStatus.AVAILABLE)
                    {
                        if (!deviceList.ContainsKey(res.id))
                            deviceList[res.id] = new Dictionary<string, string>() {
                            { "name", "" },
                            { "isConnectable", "False" }
                        };
                        if (res.nameUpdated)
                            deviceList[res.id]["name"] = res.name;
                        if (res.isConnectableUpdated)
                            deviceList[res.id]["isConnectable"] = res.isConnectable.ToString();
                        if (deviceList[res.id]["name"] == targetDeviceName && deviceList[res.id]["isConnectable"] == "True")
                        {
                            selectedDeviceId = res.id;
                            StopDeviceScan();
                        }
                    }
                    else if (status == BleApi.ScanStatus.FINISHED)
                    {
                        StartCoroutine(ScanServiceAndCharacteristicsToSubscribe());
                    }
                } while (status == BleApi.ScanStatus.AVAILABLE);
            }
            if (isScanningServices)
            {
                BleApi.Service res;
                do
                {
                    status = BleApi.PollService(out res, false);
                    if (status == BleApi.ScanStatus.AVAILABLE)
                    {
                        serviceList.Add(res.uuid);
                    }
                    else if (status == BleApi.ScanStatus.FINISHED)
                    {
                        isScanningServices = false;
                    }
                } while (status == BleApi.ScanStatus.AVAILABLE);
            }
            if (isScanningCharacteristics)
            {
                BleApi.Characteristic res;
                do
                {
                    status = BleApi.PollCharacteristic(out res, false);
                    if (status == BleApi.ScanStatus.AVAILABLE)
                    {
                        string name = res.userDescription != "no description available" ? res.userDescription : res.uuid;
                        characteristicsList.Add(name);
                    }
                    else if (status == BleApi.ScanStatus.FINISHED)
                    {
                        isScanningCharacteristics = false;
                    }
                } while (status == BleApi.ScanStatus.AVAILABLE);
            }
            if (isSubscribed)
            {
                BleApi.BLEData res;
                while (BleApi.PollData(out res, false))
                {
                    //string text = BitConverter.ToString(res.buf, 0, res.size);
                    // string text = Encoding.ASCII.GetString(res.buf, 0, res.size);
                    byte[] bytes = new byte[res.size];
                    Array.Copy(res.buf, bytes, res.size);
                    _receiveDataTime = Time.realtimeSinceStartup;
                    OnCharacteristicChanged?.Invoke(bytes);
                }
            }
            {
                BleApi.ErrorMessage res;
                BleApi.GetError(out res);
                if (lastError != res.msg)
                {
                    Error(res.msg);
                    lastError = res.msg;
                    if (lastError.Contains("SendDataAsync") && isSubscribed)
                    {
                        HandleConnectFail();
                    }
                }
            }
        }

        void LateUpdate()
        {
            if (
                _heartBeatInterval > 0 && 
                isSubscribed && 
                Time.realtimeSinceStartup - _connectedTime >= _heartBeatInterval &&
                Time.realtimeSinceStartup - _receiveDataTime >= _heartBeatInterval
            ) HandleConnectFail();
        }

        private bool Connect()
        {
            if (isConnectLocking || isScanningDevices)
            {
                Warn("Connect Invalid, because is in connect.");
                return false;
            }
            BleApi.StartDeviceScan();
            isConnectLocking = true;
            isScanningDevices = true;
            Log("Start Connect");
            return true;
        }

        private void StopDeviceScan()
        {
            if (!isScanningDevices) return;
            BleApi.StopDeviceScan();
            isScanningDevices = false;
        }

        private IEnumerator ScanServiceAndCharacteristicsToSubscribe()
        {
            isSubscribing = true;

            if (selectedDeviceId == null)
            {
                HandleConnectFail();
                yield break;
            }
            Log("SelectedDeviceId OK");

            BleApi.ScanServices(selectedDeviceId);
            isScanningServices = true;
            serviceList.Clear();

            while (isScanningServices) yield return null;

            bool findTargetService = false;

            foreach (string service in serviceList)
            {
                if (service == targetService)
                {
                    findTargetService = true;
                    Log("FindTargetService OK");
                    break;
                }
            }

            if (!findTargetService)
            {
                HandleConnectFail();
                yield break;
            }

            BleApi.ScanCharacteristics(selectedDeviceId, targetService);
            isScanningCharacteristics = true;
            characteristicsList.Clear();

            while (isScanningCharacteristics) yield return null;

            bool findTargetCharacteristicsNotify = false;
            bool findTargetCharacteristicsWrite = false;

            foreach (string characteristics in characteristicsList)
            {
                if (characteristics == targetCharacteristicsNotify)
                {
                    findTargetCharacteristicsNotify = true;
                    Log("FindTargetCharacteristicsNotify OK");
                }
                else if (characteristics == targetCharacteristicsWrite)
                {
                    findTargetCharacteristicsWrite = true;
                    Log("FindTargetCharacteristicsWrite OK");
                }
            }

            if (!findTargetCharacteristicsNotify || !findTargetCharacteristicsWrite)
            {
                HandleConnectFail();
                yield break;
            }

            BleApi.SubscribeCharacteristic(selectedDeviceId, targetService, targetCharacteristicsNotify, false);
            isSubscribed = true;
            isSubscribing = false;
            Log("SubscribeCharacteristicNotify OK");

            _connectedTime = Time.realtimeSinceStartup;
            OnConnected?.Invoke();
        }

        private void HandleConnectFail()
        {
            if (selectedDeviceId != null) BleApi.Disconnect(selectedDeviceId);
            bool isLockBefore = isConnectLocking;
            ReinitAfterConnectFail();
            if (isLockBefore) OnConnectionFailed?.Invoke();
        }

        private void ReinitAfterConnectFail()
        {
            isConnectLocking = false;
            isScanningDevices = false;
            isScanningServices = false;
            isScanningCharacteristics = false;
            isSubscribed = false;
            isSubscribing = false;
            selectedDeviceId = null;
            deviceList.Clear();
            serviceList.Clear();
            characteristicsList.Clear();
        }

        private bool Write(string text)
        {
            if (!isSubscribed) return false;
            byte[] payload = Encoding.ASCII.GetBytes(text);
            BleApi.BLEData data = new BleApi.BLEData();
            data.buf = new byte[512];
            data.size = (short)payload.Length;
            data.deviceId = selectedDeviceId;
            data.serviceUuid = targetService;
            data.characteristicUuid = targetCharacteristicsWrite;
            for (int i = 0; i < payload.Length; i++)
                data.buf[i] = payload[i];
            // no error code available in non-blocking mode
            BleApi.SendData(in data, false);
            Log("Write(" + text + ")");
            return true;
        }

        private bool Disconnect()
        {
            if (!isConnectLocking)
            {
                Warn("Disconnect Invalid, because not in connect.");
                return false;
            }
            if (isSubscribing)
            {
                Warn("Disconnect Invalid, because is subscribing.");
                return false;
            }
            if (isScanningDevices) StopDeviceScan();
            if (selectedDeviceId != null) BleApi.Disconnect(selectedDeviceId);
            ReinitAfterConnectFail();
            Log("Disconnect OK");
            return true;
        }
    }
    public class BleApi
    {
        public enum ScanStatus { PROCESSING, AVAILABLE, FINISHED };

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        public struct DeviceUpdate
        {
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)]
            public string id;
            [MarshalAs(UnmanagedType.I1)]
            public bool isConnectable;
            [MarshalAs(UnmanagedType.I1)]
            public bool isConnectableUpdated;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 50)]
            public string name;
            [MarshalAs(UnmanagedType.I1)]
            public bool nameUpdated;
        }

        [DllImport("BleWinrtDll.dll", EntryPoint = "StartDeviceScan")]
        public static extern void StartDeviceScan();

        [DllImport("BleWinrtDll.dll", EntryPoint = "PollDevice")]
        public static extern ScanStatus PollDevice(ref DeviceUpdate device, bool block);

        [DllImport("BleWinrtDll.dll", EntryPoint = "StopDeviceScan")]
        public static extern void StopDeviceScan();

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        public struct Service
        {
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)]
            public string uuid;
        };

        [DllImport("BleWinrtDll.dll", EntryPoint = "ScanServices", CharSet = CharSet.Unicode)]
        public static extern void ScanServices(string deviceId);

        [DllImport("BleWinrtDll.dll", EntryPoint = "PollService")]
        public static extern ScanStatus PollService(out Service service, bool block);

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        public struct Characteristic
        {
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)]
            public string uuid;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 100)]
            public string userDescription;
        };

        [DllImport("BleWinrtDll.dll", EntryPoint = "ScanCharacteristics", CharSet = CharSet.Unicode)]
        public static extern void ScanCharacteristics(string deviceId, string serviceId);

        [DllImport("BleWinrtDll.dll", EntryPoint = "PollCharacteristic")]
        public static extern ScanStatus PollCharacteristic(out Characteristic characteristic, bool block);

        [DllImport("BleWinrtDll.dll", EntryPoint = "SubscribeCharacteristic", CharSet = CharSet.Unicode)]
        public static extern bool SubscribeCharacteristic(string deviceId, string serviceId, string characteristicId, bool block);

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        public struct BLEData
        {
            [MarshalAs(UnmanagedType.ByValArray, SizeConst = 512)]
            public byte[] buf;
            [MarshalAs(UnmanagedType.I2)]
            public short size;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string deviceId;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string serviceUuid;
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 256)]
            public string characteristicUuid;
        };

        [DllImport("BleWinrtDll.dll", EntryPoint = "PollData")]
        public static extern bool PollData(out BLEData data, bool block);

        [DllImport("BleWinrtDll.dll", EntryPoint = "SendData")]
        public static extern bool SendData(in BLEData data, bool block);

        [DllImport("BleWinrtDll.dll", EntryPoint = "Disconnect", CharSet = CharSet.Unicode)]
        public static extern void Disconnect(string deviceId);

        [DllImport("BleWinrtDll.dll", EntryPoint = "Quit")]
        public static extern void Quit();

        [StructLayout(LayoutKind.Sequential, CharSet = CharSet.Unicode)]
        public struct ErrorMessage
        {
            [MarshalAs(UnmanagedType.ByValTStr, SizeConst = 1024)]
            public string msg;
        };

        [DllImport("BleWinrtDll.dll", EntryPoint = "GetError")]
        public static extern void GetError(out ErrorMessage buf);
    }
}